Virginia Tech Weed Identification Guide

Bulbous Buttercup: Ranunculus bulbosus

bulbousbutr8-15.jpg (67157 bytes) Weed Description:  A low-growing perennial with divided leaves and distinctive yellow flowers.  The buttercups are common weeds of turfgrass, lawns, pastures, hay fields, and occasionally landscapes.   Bulbous buttercup is found throughout the eastern and western United States.
Seedlings: Cotyledons occur on petioles and are oval to elliptic in outline.  The first true leaves are hairy and divided into 3 lobes.  True leaves also occur on petioles.

Roots:  The base of the plant is thickened into a structure known as a corm, which resembles a bulb.  Corms aren't always as evident as that pictured below.  In younger plants, a thickened base may be all that occurs.

bulbbutter9-20e.jpg (134850 bytes)
bulbbutter9-20b.jpg (122571 bytes) Leaves:  Basal leaves occur on long petioles and are divided into 3 lobes.  As the leaves become more mature, the central lobe occurs on it's own stalk while the lateral lobes are attached directly to the main leaf petiole.  Stem leaves are generally smaller than the basal leaves and arranged alternately along the stem.  Stem leaves are also less distinctively lobed than the basal leaves.
Stems:  Erect, from 8 to 24 inches in height but generally more prostrate in turfgrass and lawns.  Stems are occasionally hairy near the base and end in a typical buttercup flower. bulbbutr2.jpg (184811 bytes)
bulbbutr.jpg (34893 bytes) Flowers:  Single flowers occur on flower stalks at the ends of stems.  Flowers range from 1/2 to 1 1/4 inches wide and consist of 5 to 7 bright yellow petals.

Fruit:   An achene.

Identifying Characteristics:   The distinctive buttercup flowers, leaves that are divided into 3 parts, and thickened 'bulbous' base are all characteristics that help to distinguish bulbous buttercup from other similar species.  Several other buttercup species are common, such as Corn Buttercup (Ranunculus arvensis), however none of the other buttercups have the corms like bulbous buttercup.   Additionally, the stem leaves of corn buttercup are essentially linear in outline unlike bulbous buttercup.  Bird's-foot Violet (Viola pedata) also resembles the buttercup species prior to flowering, however this plant has leaves that are divided into 3 lobes with each lobe being divided further. bulbbutter9-20d.jpg (165000 bytes)